Auxiliary make-up circuit for gas turbine plants



Apnl 12, 1949. w. TRAUPEL 2,467,167 AUXILIARY MAKE-UP CIRCUIT FOR GAS TURBINE PLANTS Filed Jan. so. 1945 INVENTOR ATTORNEYS Patented Apr. 12, 1949 AUXILIARY MAKE-UP CIRCUIT FOR GAS I TURBINE PLANTS Walter Traupel, Wlnterthur,

signer to Suizer Fredres,

terthur, Switzerlan Switzerland, u-

Socit Anonyme, Win- Application January 30, 1945, Serial No. 575,294

In Switzerland March 18, 1944 8 Claims. l

The invention relates to a gas turbine plant in which air from the atmosphere is continuously supplied to a circuit of working medium. The invention is characterised in that at least one compressor is coupled by means of a disconnectible coupling to the turbine giving up the useful output, this compressor introducing the air into the circuit at a higher pressure when the output of the whole plant is greater, while at a smaller output the compressor is cut out by means of the coupling and the air is supplied to thecircuit at a lower pressure. It is expedient for the air compressor to be driven by the useful output turbine by means of a fluid coupling that can be emptied.

An embodimentof the invention designed as a ships propulsion plant is explained below in more detail with the aid of the drawing, which illustrates that embodiment diagrammatically.

The working medium compressed by the lowpressure compressor l' passes through the intermediate cooler 2 into the high-pressure compressor 3 and is preheated in the tubes of a recuperator-heat exchanger 4. At the point 6 in the outlet pipe of the recuperator the flow of working medium is divided up. A part passes through the pipe 1 into the heater 8 and is further heated while flowing over the heat-exchange tubes of the heater.

The working medium now compressed to the highest working pressure and heated to the highest working temperature passes through the pipe 9 into the turbine 10, is there expanded and then flows through the pipe ll into the heat exchanger 4. While flowing through the heat-exchanger tubes it gives up part of its residual heat to the compressed working medium. A further part of its residual heat is given up to a cooling medium in the cooler l2, whereupon the working medium flows back to the low-pressure compressor I and the circuit here recommences.

A further part of the flow of working medium divided at the point 6 is extracted from the circuit and supplied through the pipe l3 to the burner M of the gas heater 8. The combustion gases flow through the heat-exchange tubes and then pass through the pipe l5 into the turbine Hi, from which after expansion they are led off through the pipe I! to be disposed of in any of the known ways of handling gas turbine exhaust. Through the pipes I8 or air is continuously supplied as make-up air for the part extracted at the point 8, to the open circuit of working medium taking place in the plant.

The turbine l0 operated by the flow of working medium in the circuit drives the compressors I and 3. Further, an electric auxiliary machine 22 is coupled to the compressors I and 3, and this can supply additional power to the compressors when the plant is being started up and also in case of lack of power during service. If on the contrary an excess of power presents itself in the turbine I0, this can be led' ofi through the electric machine 22, in the form of electric energy, to themains. The turbine l6, operated by the quantity extracted, generates the useful output given up to the outside. This useful output turbine drives, for instance, the ship's propeller 2| through the reduction gear [9, 20.

The two compressors 23 and 24 are coupled to the turbine I6 generating the useful output through the reduction gear I9, 20 and the fluid couplings 25 and 26 respectively, which can be emptied. The compressor 23 draws air from the atmosphere through the pipe 21 and conducts it in a compressed state to the cooler 28. The cooled air is supplied through the pipe 29 to the compressor 24 and finally introduced through the pipe 3!! into the circuit of the working medium at the point 3| between the heat exchanger 4 and the cooler l2. At the point 32 a pipe 33 connects up, through which air can be supplied to the compressor 24 direct from the atmosphere when required. The two valve members 34 and 35 serve for switching over the service. A further valve member 36 prevents any flow into the pipe 30- in case the two compressors 23 and 24 should not be in service.

If when the vessel is proceeding at cruising speed the plant is to produce asmall output only,

the member 36 in the pipe 30 is closed. The compressor I then draws in working medium as it becomes avaflable through the cooler l2 and also fresh air through the non-return member 31 from the pipe l8. Approximately atmospheric pressure will then prevail at the inlet of the compressor I. The compressors I and 3 compress this working medium to a pressure of about 5 atmospheres, which will still prevail, apart from the atmospheres into the circuit at the point 3 I. The

non-return member 31 is closed by the increased pressure, so that escape of the air through the pipe i8 is prevented. Working medium then flows to the compressor 1 at the delivery pressure of the compressor 24, apart from the slight pressure drop resulting from resistance to flow. The final pressure at the outlet from the compressor 3 .and the inlet pressure into the turbines l6 and ID are correspondingly raised to about 20 atmospheres, so that a higher power is available for driving the ship's propeller 2|.

For travel at top speed the compressor 23 is also brought into serviceby filling the fluid coupling 25. The member 34 is opened and the member 35 closed, so that air is drawn in from the atmosphere through the pipe 21, cooled in a state of intermediate compression by the cooler 28 and further compressed by the compressor 24. The two compressors together then compress the air to about 8 atmospheres. This pressure, less the slight pressure drop resulting from resistance to flow, also prevails at the inlet to the compressor l, and thus the delivery pressure of the compressor 3 rises to about 40 atmospheres. The whole sequence of pressures in the circuit is raised to 8 times the pressures prevailing in service at cruising speed. The output given up to the outside then rises to 15 times the output at slow speed.

The advantage of the plant described consists in that the turbines can be designed for the conditions at cruising speed, for which the best efilciency is maintained. The output of the plant can nevertheless be raised to a multiple of the output at cruising speed.

While I have described my invention in detail in terms of a specific structure, I do not wish to be limited to the details of the disclosed construction. It is apparent that many changes can be made therein within the spirit of my invention. For example, in a twin-screw installation with separate useful output turbines on each shaft, the low-pressure auxiliary make-up compressor could be driven by disconnectable coupling from one shaft and-its high pressure counterpart from the other. Or other known forms of disconnectable coupling can be substie tuted for the preferred fluid type illustrated. Hence, for an understanding of the scope of the invention, reference is to be made to the appended claims.

I claim:

1. In a gas turbine plant, a working medium circuit including a compressor, a gas heater, a turbine and conduit means for conducting a gaseous working medium in the circuit through the compressor, the gas heater, the turbine and back to the compressor, a second turbine driven by working medium extracted from the circuit, one

- of said turbines driving said circuit compressor and the other of said turbines driving the plant useful load, disconnectable coupling means on the one of said turbines driving the useful load,

a second compressor driven from said coupling means, an intake from the atmosphere leading to said second compressor, and conduit means for delivering the output of said second compressor to a spot in the circuit before the first compressor.

2. The combination of claim 1 in which the disconnectable coupling means comprises a fluid coupling.

3. In a gas turbine plant, a working medium circuit including a compressor, a gas heater, a turbine and conduit means for conducting a gaseous working medium in the circuit through the compressor, the gas heater, the turbine and back to the compressor, a second turbine driven by working medium extracted from the circuit, one of said turbines driving said circuit compressor and the other of said turbines driving the plant useful load, disconnectable coupling means on the one of said turbines driving the useful load, a second and a third compressor driven from said coupling, anintake from the atmosphere leading to said second compressor, conduit means for delivering the output of saidsecond compressor to the third compressor, conduit means for delivering the output of said third compressor to a spot in the circuit before the first compressor, and an intake from the atmosphere leading to said third compressor.

4. The combination of claim 3 in which the conduit means connecting the second and third compressors contains a cooler.

5. In a gas turbine plant, a working medium circuit including a compressor, a gas heater, a turbine driving said compressor, a recuperator, a cooler and conduit means for conducting a gaseous working medium in the circuit through the compressor, the gas heater, the turbine, the recuperator and the cooler and back to the compressor, a conduit for extracting part of the working medium from the circuit and delivering it to the burner of the gas heater, a second turbine driven by the combustion gases of the gas heater and driving the plant useful load, compressor means disconnectably driven by said second turbine, an intake from the atmosphere leading to said compressor means, and conduit means for delivering the output of said compressor means to the circuit.

6. The combination of claim 5 in which the output of the compressor means is delivered to the circuit between th recuperator and the compressor.

'7. The combination of claim 6 in which an intake from the atmosphere is provided in the circuit between the cooler and the compressor.

8. In a gas turbine plant, a working medium circuit including a compressor, a gas heater, a turbine driving said compressor, a. recuperator, a cooler and conduit means for conducting a gaseous working medium in the circuit through the compressor, the gas heater, the turbine, the recuperator, the cooler and back to the compressor, intake means from the atmosphere leading to said compressor, a conduit for extracting part of the working medium from the circuit and delivering it to the burner of the gas heater, a second turbine driven by the combustion gases of the gas heater and driving the plant useful load,

compressor means disconnectably driven by said second turbine, said compressor means comprising a second and third compressor, an intake from the atmosphere leading to said second compressor, conduit means for delivering the output of said second compressor to said third compressor, conduit means for delivering the output of said third compressor to the circuit between the recuperator and the first compressor, an intake from the atmosphere to the conduit connecting said second and third compressors and valve means in the intake to the first com pressor, in the intake to the second compressor, intermediate said second and third compres sors and intermediate said third compressor and the circuit whereby air from the atmosphere can be admitted to the circuit through the first, the first and second, or the first, second and third compressors at will.

WALTER 'I'RAUPEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,959,795 Lysholm May 22, 1934 2,341,490 Traupel Feb. 8, 1944 10 2,358,815 Lysholm Sept. 26, 1944 FOREIGN PATENTS Number Country Date 76,249 Switzerland Nov. 16, 1917 378,229 Italy Jan. 25, 1940 746,148 France Mar. 7, 1933 

